Medical image processing device, treatment system, medical image processing method, and program
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- KK TOSHIBA
- Filing Date
- 2026-01-15
- Publication Date
- 2026-07-30
Smart Images
Figure JP2026001102_30072026_PF_FP_ABST
Abstract
Description
Medical image processing device, treatment system, medical image processing method, and program
[0001] Embodiments of the present invention relate to a medical image processing device, a treatment system, a medical image processing method, and a program. More specifically, embodiments of the present invention relate to a method for shortening the operation time required for patient positioning in a patient positioning device for adjusting to the optimal position for irradiating a target affected area, including in particle beam therapy, by sharing patient positioning information between a 3D-2D registration method and a 3D-3D registration method.
[0002] In particle beam therapy, patient positioning involves comparing a digitally reconstructed radiograph (DRR) generated from CT (Computed Tomography) images taken for treatment planning with an X-ray image taken by an X-ray device to calculate the amount of misalignment, and then moving the treatment table on which the patient is placed based on the calculated misalignment. While accurate patient positioning is necessary, longer positioning times increase the burden on both the patient and the treatment staff. Therefore, there is a need to shorten the patient positioning time.
[0003] Conventional patient positioning methods use a 3D-2D registration method (hereinafter referred to as 3D-2D positioning processing) with X-rays from two directions. This method calculates the displacement of the treatment table by comparing the irradiation position set in the CT image for treatment planning during treatment planning with the irradiation position when the patient is X-rayed immediately before treatment, and then moves the treatment table. After moving the treatment table, the X-ray device is used again to take images, compare them, calculate the displacement, and move the treatment table again. This process is repeated until the image displacement of the irradiation position is minimized. As a result, patient positioning is time-consuming and places a burden on the patient.
[0004] Patient positioning by the 3D-3D Registration method (hereinafter referred to as 3D-3D positioning process) using CT images with three-dimensional information is a patient positioning method that calculates the amount of displacement of the treatment table by comparing the irradiation positions of the CT images taken for treatment planning and the CT images taken immediately before treatment, and then moves the treatment table. Patient positioning by the 3D-3D positioning process has many advantages compared to patient positioning by the 3D-2D positioning process because it can utilize three-dimensional CT image information instead of two-dimensional X-ray images.
[0005] However, when it is difficult to perform CT imaging at the irradiation position due to restrictions on the equipment layout in the treatment room, after performing patient positioning by the 3D-3D positioning process using a CT device, it is necessary to move the treatment table to the irradiation position, and in some cases, patient positioning by the 3D-2D positioning process may be required after the movement. Therefore, in the prior art, the patient positioning device for the 3D-3D positioning process and the patient positioning device for the 3D-2D positioning are used separately. However, due to the lack of data linkage, settings related to positioning are required for each device, which may result in an increase in the time required for patient positioning.
[0006] Japanese Patent No. 5279637, Japanese Patent No. 4643544
[0007] The problem to be solved by the present invention is to provide a medical image processing device, a treatment system, a medical image processing method, and a program that can shorten the time required for positioning by integrating the functions of the 3D-2D positioning process and the 3D-3D positioning process and sharing information related to positioning between the two.
[0008] The medical image processing apparatus of this embodiment includes a 3D-3D positioning execution unit, a 3D-2D positioning execution unit, a display control unit, and a control unit. The 3D-3D positioning execution unit performs 3D-3D positioning to calculate a first displacement between a first three-dimensional fluoroscopic image, which is a three-dimensional fluoroscopic image of the patient taken during the treatment planning stage, and a second three-dimensional fluoroscopic image, which is a three-dimensional fluoroscopic image of the patient taken during the treatment stage, which is later than the treatment planning stage. The 3D-2D positioning execution unit performs 3D-2D positioning to calculate a second displacement between a DRR (Digitally Reconstructed Radiograph) image generated from the first or second three-dimensional fluoroscopic image and a two-dimensional fluoroscopic image of the patient taken during the treatment stage. The display control unit causes the results of the 3D-3D positioning process or the 3D-2D positioning process to be displayed on a display device. When one of the 3D-3D positioning process or the 3D-2D positioning process is executed, the control unit shares predetermined positioning information for one of the processes with the other.
[0009] According to the present invention, a medical image processing device, a treatment system, a medical image processing method, and a program can be provided that combine the functions of 3D-2D positioning processing and 3D-3D positioning processing, and share positioning information between them, thereby shortening the time required for positioning. Furthermore, by generating a DRR image using a second three-dimensional fluoroscopic image captured for 3D-3D positioning processing, highly accurate positioning that reflects the patient's condition immediately before treatment becomes possible.
[0010] A block diagram showing the schematic configuration of a treatment system equipped with the medical image processing device 100 of the embodiment. A block diagram showing the schematic configuration of a treatment system equipped with the medical image processing device 100 of the embodiment from a different angle than Figure 1. A block diagram focusing on the schematic configuration of the medical image processing device 100 of the embodiment. A diagram showing an example of the execution result of 3D-3D positioning processing displayed by the display device 200. A diagram showing an example of the execution result of 3D-2D positioning processing displayed by the display device 200. A diagram showing an example of the flow of sharing of region of interest information by the control unit 160. A diagram showing an example of plot display during execution of 3D-3D positioning processing. A flowchart showing an example of the processing flow executed by the medical image processing device 100 of the embodiment.
[0011] The medical image processing apparatus, treatment system, medical image processing method, and program of the embodiment will be described below with reference to the drawings.
[0012] [Overall Configuration] Figure 1 is a block diagram showing the schematic configuration of a treatment system equipped with a medical image processing device 100 of an embodiment. The treatment system 1 comprises, for example, a treatment device 10, a medical image processing device 100, and a display device 200. The treatment device 10 comprises, for example, a patient bed 12, a patient bed control unit 14, a computed tomography (CT) scanner 16 (hereinafter referred to as "CT scanner 16"), and a treatment beam irradiation gate 18.
[0013] The treatment table 12 is a movable treatment table that fixes a subject (patient) P receiving radiation therapy in a lying position, for example, by a fixing device. The treatment table 12 moves with the patient P fixed inside the annular CT scanner 16 having an opening, according to the control from the treatment table control unit 14. The treatment table control unit 14 controls the translational mechanism and rotational mechanism provided on the treatment table 12 in order to align the patient's position to the irradiation position according to the movement amount signal output by the medical image processing device 100. The translational mechanism can drive the treatment table 12 in three axial directions, and the rotational mechanism can rotate the treatment table 12 around three axes. In other words, the treatment table control unit 14 moves the treatment table 12 with six degrees of freedom by controlling the translational mechanism and rotational mechanism of the treatment table 12. The degrees of freedom that the treatment table control unit 14 controls the treatment table 12 do not have to be six degrees of freedom; they may be fewer than six degrees of freedom (for example, four degrees of freedom) or more than six degrees of freedom (for example, eight degrees of freedom). The patient bed 12 is installed so as to be movable to both positions if the position where imaging is performed by the CT scanner 16 and the position where the treatment beam B is irradiated by the treatment beam irradiation gate 18 are different.
[0014] The CT scanner 16 is an imaging device for performing three-dimensional computed tomography. The CT scanner 16 has multiple radiation sources arranged inside the annular (gantry) opening, and each radiation source emits radiation to visualize the inside of the patient P's body. In other words, the CT scanner 16 emits radiation from multiple positions around the patient P. The radiation emitted from each radiation source in the CT scanner 16 is, for example, X-rays. The CT scanner 16 uses multiple radiation detectors arranged inside the annular opening to detect the radiation emitted from the corresponding radiation source that has passed through the patient P's body and reached it. The CT scanner 16 generates a CT image of the inside of the patient P's body based on the magnitude of the radiation energy detected by each radiation detector. The CT image of patient P generated by the CT scanner 16 is a three-dimensional digital image that represents the magnitude of the degree of radiation attenuation at each location inside the body as a digital value. The CT scanner 16 outputs the generated CT image to the medical image processing device 100. The imaging of the inside of the patient P's body in the CT scanner 16, that is, the irradiation of radiation from each radiation source and the generation of CT images based on the radiation detected by each radiation detector, is controlled, for example, by an imaging control unit (not shown). The CT scanner 16 is an example of a "first imaging device".
[0015] The treatment beam irradiation gate 18 irradiates the patient P with radiation as treatment beam B to destroy the tumor (lesion), which is the target area for treatment, located within the patient P's body. Treatment beam B can be, for example, X-rays, gamma rays, electron beams, proton beams, neutron beams, or heavy ion beams. Treatment beam B is irradiated linearly from the treatment beam irradiation gate 18 to the patient P (more specifically, the tumor inside the patient P's body). The irradiation of treatment beam B at the treatment beam irradiation gate 18 is controlled, for example, by a treatment beam irradiation control unit (not shown). In the treatment system 1, the treatment beam irradiation gate 18 is an example of an "irradiation unit".
[0016] In radiation therapy, treatment plans are developed in a simulated treatment room environment. Specifically, the irradiation direction and intensity of the treatment beam B are planned by simulating the patient P's position on the treatment table 12 in the treatment room. This process involves a physician identifying the irradiation target area from the CT image, or this process is performed automatically. Therefore, CT images at the treatment planning stage are imprinted with information such as parameters representing the angle of the treatment table 12 and the patient's position (e.g., supine or prone) within the treatment room. This is also true for CT images taken immediately before radiation therapy and for CT images taken during previous radiation therapy sessions. In other words, CT images taken from inside the patient P's body by the CT scanner 16 are imprinted with parameters representing the angle of the treatment table 12 and the patient's position at the time of the scan.
[0017] Figure 1 shows the configuration of a treatment device 10 comprising a CT scanner 16 and a fixed treatment beam irradiation gate 18, but the configuration of the treatment device 10 is not limited to the above configuration. For example, the treatment device 10 may be configured to include, instead of the CT scanner 16, a CT scanner in which a set of radiation sources and radiation detectors rotate inside an annular opening, a cone-beam (CB) CT scanner, a magnetic resonance imaging (MRI) scanner, an ultrasound diagnostic scanner, or any other imaging device that generates three-dimensional images of the inside of the patient P's body. For example, the treatment device 10 may be configured to include multiple treatment beam irradiation gates, such as further including a treatment beam irradiation gate that irradiates the patient P with a treatment beam from a horizontal direction. For example, the treatment device 10 may be configured to irradiate the patient P with a treatment beam from various directions by rotating around the patient P, such as by having the single treatment beam irradiation gate 18 shown in Figure 1 rotate 360 degrees around the rotation axis in the horizontal direction X shown in Figure 1. For example, instead of the CT scanner 16, the treatment device 10 may be equipped with one or more imaging devices consisting of a radiation source and a radiation detector, and this imaging device may be configured to rotate 360 degrees around the rotation axis in the horizontal direction X shown in Figure 1, thereby imaging the inside of the patient P's body from various directions. Such a configuration is called a rotating gantry type treatment device. In this case, for example, one treatment beam irradiation gate 18 shown in Figure 1 may rotate simultaneously on the same rotation axis as the imaging device. Furthermore, although the CT scanner 16 and the treatment beam irradiation gate 18 are installed in close proximity in Figure 1, the CT scanner 16 and the treatment beam irradiation gate 18 may be installed in separate locations, and their positions may be moved relative to each other by the treatment table 12 on which the patient P is placed.
[0018] The medical image processing device 100 outputs a movement signal to the bed control unit 14 to move the bed 12 to match the position of the patient P to the same position as during the treatment planning. In other words, the medical image processing device 100 outputs a movement signal to the bed control unit 14 to move the patient P to a position and posture in which the treatment beam B can be appropriately irradiated to the tumor or tissue to be treated in radiation therapy.
[0019] The display device 200 displays images to present various information about the treatment system 1 to the radiation therapist (such as a doctor) using the treatment system 1, including during the process of aligning the patient P in the medical image processing device 100. The display device 200 displays various images such as CT images and X-ray fluoroscopy images output by the medical image processing device 100, or images on which various information is superimposed. Here, various information includes, for example, patient information (age, sex, height, weight, etc.), image acquisition conditions (acquisition site, presence or absence of contrast agent, tube voltage, tube current, etc.), date and time of acquisition, or patient position (head supine, feet prone, etc.). The display device 200 is, for example, a liquid crystal display (LCD). The radiation therapist can obtain information for performing radiation therapy using the treatment system 1 by visually confirming the images displayed on the display device 200. The treatment system 1 may be configured to include a user interface, such as an operating unit (not shown), which is operated by the person performing the radiation therapy, allowing various functions performed by the treatment system 1 to be operated manually.
[0020] Figure 2 is a block diagram showing the schematic configuration of a treatment system equipped with the medical image processing device 100 of the embodiment, from a different angle than Figure 1. In addition to the configuration shown in Figure 1, the treatment system 1 includes, for example, two radiation sources 20 (radiation source 20-1 and radiation source 20-2) and two radiation detectors 30 (radiation detector 30-1 and radiation detector 30-2).
[0021] Radiation source 20-1 irradiates patient P with radiation r-1 from a predetermined angle for fluoroscopy. Radiation source 20-2 irradiates patient P with radiation r-2 from a predetermined angle different from that of radiation source 20-1 for fluoroscopy. Radiation r-1 and radiation r-2 are, for example, X-rays. Figure 1 shows a case where X-ray imaging is performed from two directions on patient P, who is fixed on a bed 12. Note that in Figure 1, the control unit that controls the irradiation of radiation r by radiation source 20 is omitted from the illustration.
[0022] Radiation detector 30-1 detects radiation r-1 that has been irradiated from radiation source 20-1 and passed through the body of patient P, and generates an X-ray fluoroscopic image of the inside of patient P corresponding to the energy magnitude of the detected radiation r-1. Radiation detector 30-2 detects radiation r-2 that has been irradiated from radiation source 20-2 and passed through the body of patient P, and generates an X-ray fluoroscopic image of the inside of patient P corresponding to the energy magnitude of the detected radiation r-2. Radiation detector 30 is arranged in a two-dimensional array of X-ray detectors, and generates a digital image as an X-ray fluoroscopic image, representing the energy magnitude of the radiation r that reached each X-ray detector as a digital value. Radiation detector 30 is, for example, a flat panel detector (FPD), an image intensifier, or a color image intensifier. In the following description, each radiation detector 30 is assumed to be an FPD. The radiation detector 30 (FPD) outputs each generated X-ray fluoroscopic image to the medical image processing device 100. Note that in Figure 1, the control unit that controls the generation of X-ray fluoroscopic images by the radiation detector 30 is omitted from the illustration. The combination of the radiation source 20 and the radiation detector 30 is an example of a "second imaging device".
[0023] Figure 2 shows a configuration in which the treatment system 1 comprises two sets of radiation sources 20 and radiation detectors 30. However, the number of combinations of radiation sources 20 and radiation detectors 30 that the treatment system 1 comprises is not limited to two. For example, the treatment system 1 may comprise three or more sets of radiation sources 20 and radiation detectors 30. Alternatively, the treatment system 1 may comprise only one imaging device (one set of radiation sources 20 and radiation detectors 30). Hereinafter, the combination of radiation sources 20 and radiation detectors 30 may be referred to as an "X-ray imaging device."
[0024] The various components shown in Figures 1 and 2 may be connected to each other by wires, or they may be connected wirelessly, for example, by a LAN (Local Area Network) or a WAN (Wide Area Network).
[0025] [Medical Image Processing Device] The medical image processing device 100 of the embodiment will be described below. Figure 3 is a block diagram mainly showing the schematic configuration of the medical image processing device 100 of the embodiment. The medical image processing device 100 includes, for example, a first image acquisition unit 110, a second image acquisition unit 120, a 3D-3D positioning execution unit 130, a 3D-2D positioning execution unit 140, a display control unit 150, a control unit 160, and a storage unit 170. The storage unit 170 stores, for example, patient information 172, treatment information 174, and region of interest information 176.
[0026] Of the components of the medical image processing device 100, the first image acquisition unit 110, the second image acquisition unit 120, the 3D-3D positioning execution unit 130, the 3D-2D positioning execution unit 140, the display control unit 150, and some or all of the control unit 160 are realized by a hardware processor such as a CPU (Central Processing Unit) executing a program (software). Some or all of these components may be realized by hardware (including circuitry) such as LSI (Large Scale Integration), ASIC (Application Specific Integrated Circuit), FPGA (Field-Programmable Gate Array), and GPU (Graphics Processing Unit), or by the cooperation of software and hardware. Some or all of the functions of these components may be realized by a dedicated LSI. The program may be stored in advance in a storage device (a storage device equipped with a non-transient storage medium) such as ROM (Read Only Memory), RAM (Random Access Memory), HDD (Hard Disk Drive), or flash memory provided by the medical image processing device 100, or it may be stored in a removable storage medium (a non-transient storage medium) such as a DVD or CD-ROM, and installed in the HDD or flash memory of the medical image processing device 100 when the storage medium is inserted into the drive device provided by the medical image processing device 100. The program may also be downloaded from another computer device via a network and installed in the HDD or flash memory of the medical image processing device 100.
[0027] The storage unit 170 can be an HDD, flash memory, RAM (Random Access Memory), etc. The storage unit 170 may also be a NAS (Network Attached Storage) device that can be accessed by the medical image processing device 100 via a network. The storage unit 170 stores information such as patient information 172, treatment information 174, and region of interest information 176.
[0028] The first image acquisition unit 110 acquires a first image of patient P before treatment and parameters (and / or treatment planning data) associated with that first image. The first image is a three-dimensional CT image representing the three-dimensional shape of the patient P's body, taken, for example, by a CT scanner 16 during the treatment planning stage when performing radiation therapy. The first image is used to determine the direction (path including inclination and distance, etc.) and intensity of the treatment beam B irradiated onto patient P during radiation therapy. The first image is an example of a "first three-dimensional fluoroscopic image".
[0029] The second image acquisition unit 120 acquires a second image of patient P immediately before the start of radiation therapy, and parameters associated with that second image. The second image is a three-dimensional CT image representing the three-dimensional shape of the inside of patient P's body, taken, for example, by a CT scanner 16, in order to adjust the position of patient P when irradiating with the treatment beam B during radiation therapy (i.e., positioning). In other words, the second image is an image taken by the CT scanner 16 immediately before irradiating with the treatment beam B from the treatment beam irradiation gate 18. In this case, the first image and the second image were taken at different times, but the method of taking each image is the same. The second image is an example of a "second three-dimensional fluoroscopic image".
[0030] The 3D-3D positioning execution unit 130 performs 3D-3D positioning processing to align the position of patient P when performing radiation therapy, based on the first image acquired by the first image acquisition unit 110 and the second image acquired by the second image acquisition unit 120. More specifically, for example, the medical image processing device 100 calculates the amount of three-dimensional displacement (hereinafter sometimes referred to as the "first displacement amount") between the first image acquired by the first image acquisition unit 110 and the second image acquired by the second image acquisition unit 120.
[0031] Next, the medical image processing device 100 outputs a movement amount signal to the bed control unit 14 to move the bed 12 on which the patient is placed and fixed by a first displacement amount, and the bed control unit 14 moves the bed 12 by the first displacement amount. In another embodiment, if the CT scanning device 16 and the treatment beam irradiation gate 18 are installed at separate locations, the medical image processing device 100 may output a movement amount signal to the bed control unit 14 to move the bed 12 by the distance between the CT scanning position and the irradiation position plus the first displacement amount, and the bed control unit 14 may move the bed 12 by the distance plus the first displacement amount.
[0032] In conventional technology, when positioning a patient in radiotherapy, the DRR (Digitally Reconstructed Radiograph) image generated from CT images taken during the treatment planning stage is compared with the X-ray fluoroscopy image taken during the treatment stage (3D-2D positioning), and the patient's bed 12 is moved by the specified amount of displacement to perform positioning. On the other hand, unlike X-ray fluoroscopy images, CT images include not only positional information about bones such as the skull, but also positional information about spaces such as the anterior horn of the lateral ventricle and internal organs. Therefore, by performing 3D-3D positioning processing by the 3D-3D positioning execution unit 130, more accurate positioning can be achieved.
[0033] The 3D-2D positioning execution unit 140 performs a 3D-2D positioning process that compares a DRR image generated from the first or second image with an X-ray fluoroscopic image of the patient taken during the treatment phase. More specifically, the 3D-2D positioning execution unit 140 calculates the amount of three-dimensional displacement (hereinafter sometimes referred to as the "second displacement") between the DRR image generated from the first or second image and an X-ray fluoroscopic image of the patient taken after moving the patient's bed 12, on which the patient is placed and fixed, by a first displacement amount. The first image is taken during the treatment planning phase, while the second image is taken immediately before treatment. For this reason, the second image may more accurately reflect the patient's body shape and organ condition during the treatment phase compared to the first image. Therefore, by having the 3D-2D positioning execution unit 140 perform the 3D-2D positioning process using the DRR image generated from the shared second image, it becomes possible to perform a more accurate positioning that is more in line with the patient's current condition compared to using the first image. For example, if the calculated second displacement is less than the threshold, the radiation therapist approves the positioning. On the other hand, if the calculated second displacement is greater than or equal to the threshold, the bed control unit 14 moves the bed 12 by the calculated second displacement, takes another X-ray fluoroscopic image of the patient, and the 3D-2D positioning execution unit 140 performs the 3D-2D positioning process again using the captured X-ray fluoroscopic image. The above process is repeated until the positioning is finally approved by the radiation therapist.
[0034] The display control unit 150 displays various information processed by the medical image processing device 100 on the display device 200. More specifically, the display control unit 150 displays on the display device 200, switchable between the results of the 3D-3D positioning process performed by the 3D-3D positioning execution unit 130 and the results of the 3D-2D positioning process performed by the 3D-2D positioning execution unit 140. For example, as a result of the 3D-3D positioning process, the display control unit 150 may display on the display device 200 the first image and the second image in a comparable manner, and also display the calculated first displacement amount. Alternatively, as a result of the 3D-2D positioning process, the display control unit 150 may display on the display device 200 the DRR image generated from the first or second image and the X-ray fluoroscopic image of the patient taken during the treatment stage in a comparable manner, and also display the calculated second displacement amount.
[0035] [Sharing of Positioning Information] The control unit 160 controls various processes performed by the medical image processing device 100. In this embodiment, in particular, as will be described later, when one of the 3D-3D positioning process and the 3D-2D positioning process is performed, the control unit 160 shares predetermined information regarding the positioning of one of the processes with the other of the 3D-3D positioning process and the 3D-2D positioning process. Here, the predetermined information includes some or all of the patient information 172, treatment information 174, and region of interest information 176 stored in the storage unit 170. The predetermined information may also include data from the second image captured and used in the 3D-3D positioning process. This makes it possible for the 3D-2D positioning execution unit 140 to smoothly generate a DRR image using the shared second image without having to acquire image data again.
[0036] Patient information 172 is various information about the patient to be treated. Patient information 172 includes, for example, the patient's name, date of birth, gender, and ID. Treatment information 174 is various information about the patient's treatment. Treatment information 174 includes, for example, parameters representing the angle of the treatment table 12 and the patient's position when the inside of the patient P is scanned by the CT scanner 16 during the treatment planning stage, parameters representing the irradiation direction and intensity when the treatment beam B is irradiated onto the patient P, and information indicating the region of interest that the treatment beam B is targeted for irradiation. The region of interest can also be said to be the region that is the focus of positioning (the target for calculating the amount of displacement) during positioning.
[0037] Patient information 172 and treatment information 174 are pre-set during the treatment planning stage by the radiation therapist (such as a physician) using the treatment system 1. Region of interest information 176 is information indicating the region of interest to be irradiated with radiation. Region of interest information 176 may be pre-set by the radiation therapist, or it may be manually set by the radiation therapist, for example, during the execution of 3D-3D positioning or 3D-2D positioning. If the region of interest is manually set by the radiation therapist, treatment information 174 does not need to include information about the region of interest.
[0038] Figure 4 shows an example of the execution result of the 3D-3D positioning process displayed by the display device 200. In Figure 4, tab TB represents a button for switching between displaying the results of the 3D-3D positioning process and displaying the results of the 3D-2D positioning process. Figure 4 shows the case where the display of the results of the 3D-3D positioning process is selected.
[0039] Region R1 shows the first displacement amount calculated by the 3D-3D positioning execution unit 130. In Figure 4, the first displacement amount is represented by six degrees of freedom, taking into account the yaw angle, roll angle, and pitch angle in addition to the displacement amount of the three-dimensional position. Region R2 shows a cross-section of the CT image (i.e., the first image) taken during the treatment planning stage. As will be described later, various positioning-related information is displayed in region R2, such as the displacement amount of points plotted on the image cross-section. Region R3 shows the first image (and / or the second image) as an axial cross-section, a sagittal cross-section, and a coronal cross-section.
[0040] As mentioned above, unlike X-ray fluoroscopy images, CT images include not only positional information about bones such as the skull, but also positional information about spaces such as the anterior horn of the lateral ventricle and internal organs. Therefore, the 3D-3D positioning execution unit 130 may accept a selection from multiple parts such as bones, spaces, and internal organs on the display device 200 and perform 3D-3D positioning to match the selected part (in other words, it may accept a selection from multiple automatic positioning methods). This makes it possible to select the optimal positioning method according to the situation and shorten the positioning time.
[0041] Furthermore, in Figure 4, button B1 is a button used by the control unit 160 to share predetermined positioning information with the 3D-2D positioning execution unit 130. That is, when the radiation therapist presses button B1, the control unit 160 shares the aforementioned predetermined information with the 3D-2D positioning execution unit 130, and the 3D-2D positioning execution unit 130 performs 3D-2D positioning processing based on the DRR image generated from the first or second image, the patient's X-ray fluoroscopic image taken during the treatment stage, and the shared predetermined information. At this time, the 3D-2D positioning execution unit 130 may generate a DRR image based on the second image data included in the shared predetermined information. In addition, the 3D-2D positioning execution unit 130 may be able to switch between using a DRR image generated from the first image or a DRR image generated from the second image, depending on predetermined settings or the selection of the radiation therapist. Pressing button B1 is not necessarily required. The control unit 160 may automatically share the predetermined information described above with the 3D-2D positioning execution unit 130 after the 3D-3D positioning process has been executed by the 3D-3D positioning execution unit 130, and then proceed to execute the 3D-2D positioning process.
[0042] In this regard, in conventional technology, 3D-3D positioning processing and 3D-2D positioning processing were performed separately. Therefore, when performing 3D-2D positioning processing, it was necessary to re-set the information set in 3D-3D positioning processing (for example, patient information, treatment information, region of interest information). On the other hand, according to this embodiment, the information used in 3D-3D positioning processing is shared with the 3D-2D positioning execution unit 130. This allows for smooth execution from 3D-3D positioning processing to 3D-2D positioning processing, reducing the burden on the patient.
[0043] Further, in FIG. 4, button B2 is a button for enabling fine adjustment of the result of the 3D-3D positioning process executed by the 3D-3D positioning execution unit 130. That is, when the radiation therapy operator presses button B2, the 3D-3D positioning execution unit 130 accepts fine adjustment of the first deviation amount while comparing the first image and the second image for the radiation therapy operator on the display device 200. Thereby, even when the accuracy of the first deviation amount calculated by the 3D-3D positioning execution unit 130 is low, correction by the radiation therapy operator can be enabled.
[0044] FIG. 5 is a diagram showing another example of the execution result of the 3D-2D positioning process displayed by the display device 200. FIG. 5 represents the case where the result display of the 3D-2D positioning process is selected in tab TB. In FIG. 5, when "3D-3D" is selected, the display control unit 150 switches to the result display of the 3D-3D positioning process shown in FIG. 4.
[0045] Region R1 indicates the second deviation amount calculated by the 3D-2D positioning execution unit 130. In FIG. 5, similar to the first deviation amount, the second deviation amount is expressed by six degrees of freedom considering the yaw angle, roll angle, and pitch angle in addition to the deviation amount of the three-dimensional position as an example. Region R2 shows a cross-section of the CT image (i.e., the first image) taken in the treatment planning stage. Note that region R2 may display a cross-section of the shared second image. Region R3 includes a DRR image 1 generated from the first image or the second image for a certain cross-section, an X-ray fluoroscopy image 1 of the patient taken in the treatment stage for the cross-section, a DRR image 2 generated from the first image or the second image for another cross-section, and an X-ray fluoroscopy image 2 of the patient taken in the treatment stage for the cross-section.
[0046] Furthermore, in FIG. 5, button B2 is a button for enabling fine adjustment of the result of the 3D-2D positioning process executed by the 3D-2D positioning execution unit 130. That is, when the operator of radiation therapy presses button B2, the 3D-2D positioning execution unit 130 accepts fine adjustment of the second deviation amount while comparing the DRR image (derived from the first image or the second image) with the fluoroscopic X-ray image for the operator of radiation therapy on the display device 200. Thereby, even when the accuracy of the second deviation amount calculated by the 3D-2D positioning execution unit 130 is low, correction by the operator of radiation therapy can be enabled. Furthermore, by enabling image comparison between the DRR image generated from the second image and the fluoroscopic X-ray image, the operator of radiation therapy can perform positioning with high accuracy.
[0047] FIG. 6 is a diagram showing an example of the flow of sharing region-of-interest information by the control unit 160. The left part of FIG. 6 represents the screen immediately after execution of the 3D-3D positioning execution unit 130 in the treatment stage. In the screen shown in the left part of FIG. 6, the 3D-3D positioning execution unit 130 accepts designation of the region of interest IR1 by the operator of radiation therapy on each cross-section of the CT image (that is, the first image) taken in the treatment planning stage on the display device 200. FIG. 6 represents, as an example, the case where the 3D-3D positioning execution unit 130 accepts designation of the region of interest IR1 on the body axis cross-section.
[0048] In the screen shown in the left part of FIG. 6, when the user presses button B1, the control unit 160 shares the designated region of interest IR1 with the 3D-2D positioning execution unit 130, and the 3D-2D positioning execution unit 130 performs a 3D-2D positioning process based on the DRR image generated from the first image or the second image, the fluoroscopic X-ray image of the patient taken in the treatment stage, and the shared region of interest IR1. That is, the 3D-2D positioning execution unit 130 focuses on performing 3D-2D positioning (calculating the second deviation amount) with respect to the region of interest IR1. Thereafter, as shown in the right part of FIG. 6, the display control unit 150 displays the region of interest IR1 shown in the cross-section of the CT image as the region of interest IR2 on the region R2.
[0049] Conversely, the 3D-2D positioning execution unit 130 may, on the screen on the right side of Figure 6, receive a designation of the region of interest IR2 by the radiation therapist on the display device 200, and cause the 3D-3D positioning execution unit 130 to perform 3D-3D positioning with a focus on the region of interest IR2, and the display control unit 150 may display the region of interest IR2 as the region of interest IR1 on region R2. In this way, by automatically using the region of interest information specified during the execution of either the 3D-3D positioning process or the 3D-2D positioning process for the execution of the other positioning process, the time required for patient positioning can be shortened.
[0050] [Plot Display] As another function, the 3D-3D positioning execution unit 130 may, via the display device 200, receive (and simultaneously number) the designation of one or more points on each of the axial, sagittal, and coronal cross-sections for which the two-dimensional displacement between the first image and the second image is to be calculated, calculate the two-dimensional displacement for each of those one or more points, and display them in a list. By displaying the point position displacement, the person performing the radiation therapy can easily check the displacement between the first image and the second image.
[0051] Figure 7 shows an example of a plot display during 3D-3D positioning processing. In Figure 7, points P1 to P4 represent comparison points specified by the radiation therapist. Furthermore, in Figure 7, Bars 1 to 3 represent operation bars for specifying the positions from which to extract axial, sagittal, and coronal sections from the CT image, respectively. For example, when the user operates Bar 1, the 3D-3D positioning execution unit 130 extracts a desired axial section from the CT image with respect to the user's body axis direction; when the user operates Bar 2, the 3D-3D positioning execution unit 130 extracts a desired axial section from the CT image with respect to the user's sagittal direction; and when the user operates Bar 3, the 3D-3D positioning execution unit 130 extracts a desired axial section from the CT image with respect to the user's coronal direction. In other words, the radiation therapist can manipulate Bar 1 to 3 to extract desired axial, sagittal, and coronal sections from the CT image, and then have the 3D-3D positioning execution unit 130 calculate the two-dimensional displacement on the extracted sections.
[0052] In Figure 6, Bars 1 to 3 are used to create a configuration that allows for the extraction of one axial section, one sagittal section, and one coronal section, respectively. However, the present invention is not limited to such a configuration, and multiple Bars (for example, six) may be used to create a configuration that allows for the extraction of multiple axial sections, sagittal sections, and coronal sections, each (for example, two of each).
[0053] The display control unit 150 displays the two-dimensional displacement amounts calculated by the 3D-3D positioning execution unit 130 as a list on the display device 200. Figure 7 shows, as an example, a scene in which the display control unit 150 displays a list of the two-dimensional displacement amounts calculated for specified points P1 to P4 in region R2. When a number is selected in region R2, the display control unit 150 may selectively display or focus on the cross section containing the point corresponding to the selected number. This improves the convenience of plotting points on the image cross section to check for positional displacement while positioning the patient in the 3D-3D positioning process, and shortens the time required for patient positioning.
[0054] [Processing Flow] Next, the processing flow performed by the medical image processing device 100 will be described with reference to Figure 8. Figure 8 is a flowchart showing an example of the processing flow performed by the medical image processing device 100.
[0055] First, the first image acquisition unit 110 acquires a first image of patient P taken during the treatment planning stage using the CT scanner 16 (step S100). Next, the second image acquisition unit 120 acquires a second image of patient P taken during the treatment stage using the CT scanner 16 (step S102).
[0056] Next, the 3D-3D positioning execution unit 130 performs 3D-3D positioning based on the first image acquired by the first image acquisition unit 110 and the second image acquired by the second image acquisition unit 120 (step S104). Next, the bed control unit 14 moves the bed 12 by the first displacement amount determined by the 3D-3D positioning process (step S106).
[0057] Next, the 3D-2D positioning execution unit 140 generates a DRR image from the first or second image (step S108). Next, the medical image processing device 100 takes an X-ray fluoroscopic image of patient P using an X-ray imaging device (step S110). Next, the 3D-2D positioning execution unit 140 performs 3D-2D positioning based on the DRR image (derived from the first or second image), the X-ray fluoroscopic image, and predetermined information shared from the 3D-3D positioning process (step S112). Next, the display control unit 150 displays the results of the 3D-3D positioning process and the results of the 3D-2D positioning process on the display device 200 in a switchable manner (step S114).
[0058] Next, the medical image processing device 100 determines whether the positioning has been approved by the radiation therapist (step S118). More specifically, the medical image processing device 100 may determine whether the positioning has been manually approved by the radiation therapist using an interface (IF) on the display device 200, or it may automatically determine whether the positioning has been approved by determining whether the calculated second displacement is within a threshold.
[0059] If it is determined that the positioning has been approved by the radiation therapist, the medical image processing device 100 confirms the positioning and terminates the processing in this flowchart. On the other hand, if it is determined that the positioning has not been approved by the radiation therapist, the bed control unit 14 moves the bed 12 by the second displacement amount identified by the 3D-2D positioning process (step S120), and returns the process to step S110.
[0060] In the flowchart of Figure 8, in step S106, the bed control unit 14 moves the bed 12 by the first displacement amount determined by the 3D-3D positioning process. However, if the CT scanner 16 and the treatment beam irradiation gate 18 are located at separate positions, the process in step S108 may be to move the bed 12 by the distance between the CT scanning position and the irradiation position plus the first displacement amount.
[0061] According to at least one embodiment described above, the medical image processing device 100 shares predetermined information related to the positioning process with the 3D-2D positioning process after the execution of the 3D-3D positioning process, and smoothly executes the 3D-2D positioning process without requiring the radiation therapist to manually set the necessary information again. In other words, by combining the functions of the 3D-2D positioning process and the 3D-3D positioning process and sharing positioning information between them, the time required for positioning can be shortened. Furthermore, by generating a DRR image using the second three-dimensional fluoroscopic image taken for the 3D-3D positioning process, highly accurate positioning that reflects the patient's condition immediately before treatment can be achieved.
[0062] While several embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These embodiments can be carried out in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims and their equivalents.
[0063] 1... Treatment system, 10... Treatment device, 12... Treatment table, 14... Treatment table control unit, 16... CT scanning device, 18... Treatment beam irradiation gate, 100... Medical image processing device, 110... First image acquisition unit, 120... Second image acquisition unit, 130... 3D-3D positioning execution unit, 140... 3D-2D positioning execution unit, 150... Display control unit, 160... Control unit, 170... Storage unit, 200... Display device